fix: import local plugins into markdown

[JuanM04]

Changes

Fixes #2097

Importing local plugins into markdown has been tedious, because you need to use weird syntax:

// examples/with-markdown-plugins/astro.config.mjs

// @ts-check
export default /** @type {import('astro').AstroUserConfig} */ ({
  // Enable Custom Markdown options, plugins, etc.
  markdownOptions: {
    render: [
      astroRemark,
      {
        remarkPlugins: ['remark-code-titles'],
        rehypePlugins: [
          ['rehype-autolink-headings', { behavior: 'prepend' }],
          ['rehype-toc', { headings: ['h2', 'h3'] }],
          [new URL('./add-classes.mjs', import.meta.url).pathname, { 'h1,h2,h3': 'title' }],
          'rehype-slug',
        ],
      },
    ],
  },
});

Also, the example in the documentation doesn't work: #2097

So, I replaced the input to expect a function instead of the result of an import:

// examples/with-markdown-plugins/astro.config.mjs
+ import addClasses from "./add-clasees.mjs"

// @ts-check
export default /** @type {import('astro').AstroUserConfig} */ ({
  // Enable Custom Markdown options, plugins, etc.
  markdownOptions: {
    render: [
      astroRemark,
      {
        remarkPlugins: ['remark-code-titles'],
        rehypePlugins: [
          ['rehype-autolink-headings', { behavior: 'prepend' }],
          ['rehype-toc', { headings: ['h2', 'h3'] }],
-         [new URL('./add-classes.mjs', import.meta.url).pathname, { 'h1,h2,h3': 'title' }],
+         [addClasses, { 'h1,h2,h3': 'title' }],
          'rehype-slug',
        ],
      },
    ],
  },
});

This way you can pass any function that is a unified plugin no matter where you get it. Plus, this isn't breaking because, well, import didn't work 😅

Testing

yarn test:match "plugins"

Docs

Adding a Markdown plugin

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🦋 Changeset detected

Latest commit: 12e2aee

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@astrojs/markdown-remark	Patch

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[matthewp]

Could you possibly copy this module into the test fixture? Would be nice to not couple the tests with the examples.

[JuanM04]

Done! I also added hast-util-select as a dev dependency to ensure it's installed for the tests